SciHawks

Thanks to all of you who came to the practice AP exam session. This was one of the best (top two or three) practice test experiences that I have proctored, and that is a tribute to your maturity and commitment level.
Our results were relatively very good, and, over the next week, with analysis and correction of errors: test-taking, pacing, general knowledge, you will have a good test-taking experience and result on the 2012 AP Chem exam. My goal is to get you to leave that exam with full confidence that you 1. understood practically everything on the exam and 2. were satisfied with the course preparation and test-taking experience.

If I can, I will be at the Jericho Public Library at 3PM on Sunday for general review. I will confirm this in a post by noon tomorrow.
UPDATE: I will be in the Jericho Public Library from 3:30 - 5 PM today for general extra help. See you there.


Thanks again for confirming the high quality of our small group of students who endeavored to take a course that most avoid; your achievements will be worth your effort.

AP Chem - we started a part I exam though I could tell there was not a lot of previewing done - for your own benefit, you must look at and write down the questions that you know are difficult/challenging for you.
We then began our little lesson on nuclear physics - I have posted ALL of the nuclear files on edline, so peruse them this weekend. I will discuss the rest of that mini-topic on Tuesday.
There are no more unit exams in this class, just a final that I will give in class over two days after all of the AP exams have been taken. The final will be very similar to the 2012 AP Chem exam that you took, but part I will be truncated, so that it may be taken in a single period.

Bio - took the exam on Modern Genetics.

AP Chem - we started our 3rd (of at least 12, I expect) AP exam reviews. Using these older format exams, we will cover more question types per exam, which will better prepare us for the mixture of questions on this year's exam. The hw for this is due by the end of the school day or extra help tomorrow. We covered a kinetics, a molecular bonding/structure, and an electrolytic cell problem.

Bio - we discussed two types of cloning: therapeutic (formation of a person's particular cells/tissues/organs from stem cells) and reproductive (formation of a genetically identical individuals from the donor's nucleus and a denucleated egg). We then did questions regarding applications of gel electrophoresis. Answers to the rest of the practice review questions on genetic engineering and modern genetics are on Edline. Do all of those problems tonight. Email me if you have questions.

AP Chem - we finished up Electrochem by discussing the driving of non-spontaneous cells via electrolysis i.e. electrolytic cells. These cells are used mostly for plating of precious metals onto cheaper metals at the cathode of the cell e.g. silver cations get reduced to silver on a cathode (spoon or fork, etc.) of tin. Also, these cells are used for reduction of active metals, which must immediately be put into an inert atmosphere of a noble gas or into an unreactive organic liquid like mineral oil.

We then began work on a part I AP exam, the rest of which is due for HW.

Bio - we discussed recombinant DNA technology, which is used in agriculture, medicine, and industry in order to get bacteria to produced proteins of a different organism. This is done by using restriction enzymes that cut DNA of the bacteria and of the other organism into fragments that have the same "sticky ends" of complementary bases; then, using enzymes to speed up the complementary pairing, the DNA fragments splice together to form a bigger plasmid that now also contains the DNA of the different organism. The plasmid is put into a living bacteria via mechanical, chemical, or viral VECTORS. Then, the DNA on the plasmid is replicated into each daughter cell that is produced asexually, and the DNA is transcribed and translated into the proteins that were coded for by the alleles of the other organism. Thus human insulin, spider web proteins, clotting factors, human growth hormone, or ANY protein coded for by ANY gene from ANY foreign organism can be produced by transgenic/recombinant DNA plasmid-containing bacteria.

 

AP Chem - continued our Electrochem unit with examples of standard and non-standard condition voltaic cells. By varying the concentrations/pressures of the reactants and products, we can produce different cell potentials to do more or less work per coulomb of charge that flows through the circuit

Other genetic diseases that we have discussed, such as Down's Syndrome, are due to trisomy of a given homogous pair as caused by non-disjunction during meiosis.

AP Chem - check Edline for a list of question types on Monday's exam; also, two part II exams will be posted - one with answers, for the other, I will even provide the answer to the Ksp question, so you can just complete the rest by Tuesday.

Continued with our Electrochem unit, discussing standard cell potentials, standard vs. non-standard conditions, and how non-standard conditions can change the cell potentials.
We saw how to use a table of standard cell reduction potentials to get the E-standard potential of a net reaction, warning NEVER to multiply ANY standard reduction potential because a potential is in Joules PER Coulomb, a ratio that NEVER changes with a change in the moles of reaction.
We looked at the relationship between delta G o , E o , and K.

Bio - we finished our discussion of the causes of trisomy and polyploidy, that is, nondisjunction of homologous chromosomes during meiosis I , or nondisjunction of single chromatid chromosomes during meiosis II.
We then looked at the genetic causes of four genetic diseases/failures to maintain homeostasis:
Tay-Sachs, PKU, Huntington's, and Sickle-Cell Trait.

AP Chem - we began our final unit of the course: Electrochemistry. We discussed the energy advantage of electrochemical cells, the construction of the cells, the redox reactions that occur via a conducting wire and salt bridge, the meaning of voltage/potential difference, and the conventions used in writing out Voltaic/Galvanic cells.

Bio - we discussed the various types of gene and chromosome mutations. We noted that gene mutations are just changes of ONE NUCLEOTIDE in the base sequence: addition and deletion point mutations are FRAMESHIFT mutations, whereas a substitution mutation is not.
Chromosomal alterations are either parts of an entire chromosome containing many genes are added, deleted, or transferred to or from a chromosome, or a change in the number of chromosomes in the nucleus of a cell

AP Chem - finished up our review of Thermodynamics, focusing on Gibbs Free Energy: a negative GFE means that a reaction or process is spontaneous, and the magnitude/numerical value is the maximum amount of work/energy that can be done by that reaction or process (per mole of reaction, usually).

Bio - we discussed nature vs. nurture with respect to genetics/nature setting all of an individuals potentials via the proteins that COULD be coded for by her/his alleles BUT that the nurture/environment determines whether a given allele is "turned on"/expressed/transcribed and translated into a functional protein.

AP Chem - we reviewed the thermochemistry part of the thermodynamics unit, and did two last subtopics: Hess Law diagrams of the so-called "Born-Haber" cycle, in which you relate a multi-step pathway involving ionization energies, electron affinities, heats of sublimation/vaporization/fusion, and bond dissociation energies to an overall one-step formation reaction. In any of these problems, there are usually 7 or 8 known quantities and just one unknown quantity that you solve for.
In another subtopic, we found an individual bond enthalpy based on the bond enthalpies of all of the other bonds in the reactants and products as well as the overall enthalpy change of the reaction. Again, in these problems, all but one quantity is known. Also, to avoid errors, simply add up the bond enthalpies with the appropriate realistic sign, + for bond breakage, - for bond formation.

Bio - we looked at alleles on the X sex chromosome that are not found on the shorter homologous Y sex chromosome in males; this leads to sex-linked traits that show up in different percentages between male and female offspring.
We then discussed the conventions used in pedigree charts, and deduced the possible genotypes of the individuals in the chart based on the phenotypes of the parents and offspring of several generations.

AP Chem - we did a graphical type of Hess Law calculation showing two very different pathways for a formation reaction. The overall key to this is that any one of the delta H values from one step of any pathway can be solved for if all of the other delta H values are known. This can be of great economic or practical importance if there are no simple experimental means of measuring/obtaining a particular delta H value.
Formal AP Chem exam review sessions begin this week. We will discuss each week's schedule so that you can maximize your study time with them.

AP Chem - we went through a few of the major problem types in the Thermodynamics unit; the bulk of this unit is done over the break with guided tutorials, worksheets, and videos.
Check Edline over the break for updates, corrections, and suggestions on successfully completing this unit.

Bio: we continued to discuss our example of multiple alleles by going through several permutations of possible parental and offspring blood-types as a way of including or excluding possible paternity (fathering) of offspring.
We then began to discuss traits that are coded for by alleles on the X and Y, or "sex" chromosomes".

AP Chem : We began our penultimate unit: Thermodynamics. We discussed the first law of thermo: conservation of energy, as well as state vs. non-state functions/factors.

Bio - we showed how "test-crosses" are used to determine the genotype of a parent that exhibits a "dominant" trait (yet can have a genotype of either homozygous dominant or heterozygous).
We then discussed and gave an example of two types of "intermediate" dominance: co-dominance (in which BOTH alleles are expressed, show up, INDEPENDENTLY, in the offspring phenotype) and incomplete dominance (in which both alleles' traits are BLENDED to form an intermediate version of the given trait e.g. red x white forms PINK-blended offspring).
We also discussed multiple alleles of a given gene, and gave an example of human blood types i.e. the A,B, and O alleles.

AP Chem - we did two "selective precipitation" problems in which we determined whether we could separate one ion from another in solution via precipitation via a third soluble salt.